(1) Field of the Invention
The invention relates to network communications. More specifically, the invention relates to traffic management in a network.
(2) Background
Downstream internet traffic flows on oversubscribed copper lines at rates DS-1 and below dominate the performance attributes of internet applications. Large carriers have been deploying frame relay access switches since the early nineties. ILECs and CLECs have deployed large footprints of first generation digital subscriber line access multiplexers (DSLAMs). Likewise, Internet service providers (ISP's) and cable operators have a large embedded base of legacy routers, hubs and cable modem termination systems (CMTS). These deployments have resulted in a large embedded base of legacy equipment with very limited traffic management features. Typical queuing systems are FIFO based and often a FIFO is shared across lines allowing customers to interfere with each other. One result of this FIFO queuing is that two flows directed to the same line may not be delivered in desirable order. For example, a packet or cell of a web page download or e-mail may be delivered in advance of packet or cell of the next video frame.
Bandwidth demands are continually increasing. This ever-growing demand for bandwidth necessitates traffic management techniques. While existing “last mile” infrastructure creates a performance bottleneck for downstream traffic flows, the cost of replacing this existing legacy equipment would be very high. It is useful to add traffic management capabilities to the network without replacing the legacy equipment.